The present invention relates to gaming, and in particular, to a radio frequency identification (RFID) system with an antenna array for detecting the locations of RFID tags on a gaming table.
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Tracking the location of gaming tokens in real-time on a gaming table has the potential to revolutionize the gaming industry by providing cash management and improved security. Tying this data to specific players allows casinos to create accurate player profiles while simultaneously alleviating the pit boss of mundane tasks that take years of training to hone.
Traditional RFID systems have tried to address the gaming market with limited success. In a typical RFID system, the excitation antenna defines a “working volume” within which the energy projected by the antenna is sufficient to power the RFID tag. This “working volume” is generally poorly defined with the only option to increase/decrease power to adjust the read range. But doing so extends the read range in ALL directions, introducing cross-talk errors when multiple antennas are in close proximity. Existing products on the market suffer from multiple shortcomings. First, they are limited to discrete betting spots. Second, they are limited in the chip stack heights they can read. Third, they have very poor discrimination between adjacent betting spots. Fourth, they have higher than acceptable read errors. Fifth, they have slow read rates that miss important events (e.g., placement and removal of chips, etc.).
These shortcomings limit the available technology to games where the betting spots are widely separated (e.g. a single “pot”), to detecting initial bets only (not capturing transient events such as payouts), and identifying counterfeit tokens only prior to their use on a table (not during gameplay).
U.S. Application Pub. No. 2013/0233923 discusses a ferrite core technology. The ferrite core technology overcomes many of the above-noted shortcomings, but does not address the need to track multiple separate bets placed by different bettors on a single larger betting spot (such as when “back bettors” share a betting spot with seated bettors on traditional Baccarat “racetrack” layouts). Also needed is the ability to discriminate the location of very closely spaced bets (such as can be found on a roulette table).
U.S. Application Pub. No. 2017/0228630 discusses a solution involving two intersecting antenna arrays. One array of horizontal antennas provides one coordinate, and a second array of vertical antennas provides a second coordinate. Signal strength information comparing adjacent antennas may then be used to interpolate a higher fidelity set of coordinates.
Although the approach of U.S. Application Pub. No. 2017/0228630 does work, it suffers from the simple fact that reading RFID tags takes time—and reading tags multiple times for purposes of interpolation multiplies the required time such that capturing an accurate “snapshot” of transient events with large numbers of tags may not practical in certain gaming environments.
The typical RFID system addresses the question, “Who's there?” The response is a series of unique item identifiers (e.g., serial numbers). As discussed above, the ferrite core technology discussed in U.S. Application Pub. No. 2013/0233923 is directed to addressing the additional question “Where are you?” as a way to track individual bets.
U.S. Application Pub. No. 2016/0217645 discusses using a network analyzer device prior to an RFID read, thereby being able to direct the RFID reader to only those antennas with tags present. This describes a serial approach that eliminates the “overhead” of looking for tags using an RFID reader where none are present, as using the network analyzer device takes less time than using the RFID reader.
Both U.S. Application Pub. No. 2013/0233923 and U.S. Application Pub. No. 2016/0217645 involve the placement of bets in specific areas (the betting spots). RFID tags not placed in one of the defined areas will not be read correctly. Neither of these disclosures addresses the need to detect bets placed anywhere on a larger bounded area. The additional disclosure of U.S. Application Pub. No. 2017/0228630 does address placing multiple bets within a larger bounded area. However, the system disclosed therein involved multiple RFID reads to define the coordinates of each bet, which is a time consuming process.
All three of U.S. Application Pub. No. 2013/0233923, U.S. Application Pub. No. 2016/0217645 and U.S. Application Pub. No. 2017/0228630 describe systems to identify and locate RFID tags by using signal strength information as measured by the RFID reader to determine proximity to a specific antenna. U.S. Application Pub. No. 2013/0233923 describes a system that increases the signal strength at the proper antenna, which further improves accuracy.